Casio has updated its G-Shock watch to display sports apps on screen and control music using its Bluetooth 4.0 connection.

While retaining the G-Shock look, sturdy waterproof build and long battery life, the new STB-100 is now also compatible with four sports apps for iPhone. The watch will work with Abvio's Runmeter, Walkmeter and Cyclemeter plus Wahoo Fitness.

These mean you'll be able to see pace, distance, time, pulse, cycle speed and even pedal rotations with a cadence sensor. If you think this is limiting because of the small number of apps, bear in mind that this watch will last up to two years on a single battery - something no other sports watch offers.

The STB-100 will also control your music, allowing you to play or stop songs, change volume and tracks using the watch buttons. You'll also be alerted to calls and mail while running. You can even use the watch to find your phone if it's missing.

Casio plans to expand the number of compatible fitness apps soon. Pricing and release date have not yet been announced.